As containers for packing and storing pharmaceuticals, glasses made of various materials have been used. Pharmaceuticals are roughly divided into oral agents and parenteral agents. Among them, in the case of parenteral agents, a liquid medicine packed/stored in a glass container is directly administered into the patient's blood. Therefore, there are extremely rigorous quality requirements for such glass containers. In particular, extractables from the glass into the liquid medicine may change the properties of the liquid medicine, seriously affecting the life and health of the patient. Therefore, the pharmacopoeia of each country prescribes the amount of extractables from the glass. In addition, for processing into various forms such as ampoules, vials, prefilled syringes, and cartridges, excellent viscosity characteristics are necessary.
As a glass material that meets these requirements, borosilicate glass has generally been used. Borosilicate glass for pharmaceutical containers normally contains, as constituents, SiO2, Al2O3, B2O3, Na2O, K2O, CaO, and BaO together with a small amount of fining agent.